[Primary mediastinal B-cell lymphoma presenting as cardiac tamponade: the importance of a multimodality imaging approach].

Primary mediastinal B-cell lymphoma is a rare subtype of non-Hodgkin lymphoma. Typical symptoms include cough, chest pain, and dyspnea; however, cardiac tamponade as the primary manifestation is exceedingly rare. We hereby present a case of a 83-year-old woman, who presented to our emergency department with dyspnea, cough and hypotension. On admission, echocardiography (transthoracic and transesophageal), computed tomography and cardiac magnetic resonance demonstrated a large 70 x 38 mm pericardial mass, with pericardial effusion and signs of cardiac tamponade. Positron emission tomography highlighted a marked hyperaccumulation of the tracer at the mass level, compatible with high metabolic activity. The patient underwent further workup with diagnostic and therapeutic pericardiocentesis, which demonstrated histopathology consistent with primary mediastinal B-cell lymphoma. This precise and complete diagnosis allowed the start of chemotherapy treatment with complete remission of the disease and regression of the mass in a few months. Our case highlights the importance of a complete and thorough workup for patients with chronic untraditional symptoms, like tamponade as the primary clinical presentation. Advanced multimodality imaging is crucial for early non-invasive assessment of primary cardiac tumors, helps guiding further investigations, treatment decision, assessing for potential complications, and allows documentation of therapeutic success.